South Pole Emerging As Center of Astronomy

By MALCOLM W. BROWNE

Published: December 12, 1989

SOUTH POLE, Dec. 8—
Fighting chronic fatigue caused by thin air and deadly cold, scientists here are assembling a new type of telescope that may reveal the mysterious origin of cosmic rays.

The new instrument is the first large telescope ever brought to the South Pole. It is part of a concerted campaign begun recently to exploit Antarctica's unique physical qualities for astronomical research.

Among the other new Antarctic projects expected to shed light on cosmic rays will be the launching from Ross Island later this month of a gigantic balloon.

The balloon, flown by the National Aeronautics and Space Administration, will carry four astronomical experiments, including two cosmic-ray analyzers built at the University of California at Berkeley. Scientists expect the winds at altitudes more than 100,000 feet to carry the balloon westward along the 78th parallel completely around the world in about 15 days, perhaps returning to within a few hundred miles of its launching site.

The South Pole is now basking in 24-hour-a-day summer sun at the relatively mild temperature of about minus-10 degrees Fahrenheit, and many scientists shed their red National Science Foundation parkas while working outdoors. But the touch of an unprotected fingertip to cold metal can produce pain and frostbite.

Another problem is the altitude. The South Pole is 9,300 feet high, and because the air is very cold, it is as thin as the air on top of an 11,000-foot-high elevation in a temperate zone. People living at the Pole grow accustomed to having a difficult time sleeping, tiring quickly and becoming absent-minded. A lack of oxygen makes a few of them sick.

But despite the discomforts and the monotonous view of the featureless polar plateau, astronomers are delighted with the scientific advantages of the site. Not only does night become continuous in winter, but the thin air obstructs relatively little light and radiation from space. The atmosphere is almost completely free of water vapor, which blocks infrared radiation useful to astronomers. This is because the South Polar Plateau is the driest desert in the world.

The Earth is a huge magnet, moreover, one of whose poles is in Antarctica. This creates a kind of magnetic funnel through which charged cosmic ray particles stream toward the ground in great abundance. Questions About Telescope

''The time has finally come when Antarctica is coming into its own as a major center for important astronomical research,'' said Dr. Robert M. Morse of the University of Wisconsin.

It remains to be seen whether the South Pole telescope will function properly throughout a polar night that lasts four months, when temperatures dip below minus 100 degrees Fahrenheit.

But builders of the big instrument believe they have met the challenge. The heart of the telescope is a steel rack on which are mounted 10 parabolic mirrors, each of them one meter in diameter. All the mirrors are focused to a common point, combining the faint light they receive as a single concentrated image. The mirrors are backed with electric heaters that are expected to prevent frost from forming throughout the winter.

The telescope is the work of a scientific collaboration that includes the University of Wisconsin, Purdue University, the University of Florence, Italy, and the Smithsonian Astrophysical Observatory.

Although cosmic rays were discovered 75 years ago, scientists are still not sure where they come from. The rays, which consist of streams of atomic particles and photons, a form of electromagnetic radiation, race through space at almost inconceivable energies. No particle accelerator built by human beings could ever distantly approach the energy of the most powerful cosmic rays.

When a high-energy particle collides with the Earth's atmosphere, it is destroyed. But the fireball of its destruction some six miles above the ground creates a shower of secondary particles, which in turn collide with other atoms in a series of cascades.

The final blast of particles reaches the ground in a flock that takes the form of a large pancake. The particles in this compact flock carry so much energy that biologists have theorized they might be important factors in the evolution of animal and vegetable species. The impact of a cosmic ray particle on a gene could cause the kind of mutation that may help drive the process of evolution.

Scientists theorize that cosmic rays may be produced by supernovas, the rare and violent explosions of very massive stars. In 1987 such an explosion occurred comparatively near the Earth, some 160,000 light-years away, in a satellite galaxy of the Milky Way called the Large Magellanic Cloud.

The 1987 supernova, the closest to Earth in 400 years, has been one of the main focuses of worldwide astronomical research for the past two years, and the new South Pole telescope will search for cosmic rays coming from the debris of that explosion.

If such rays are detected by the telescope, the evidence will be strengthened that supernovas are important sources of cosmic rays, although it is not fully understood why this should be. An Unusual Method